In order to save the trouble of battery replacement, a small-sized portable electronic device, e.g., a wristwatch has been equipped with a power generation function. There are various types of power generation mechanisms to be used in such an electronic device, and there have been proposed power generation mechanisms that use the principle of vibration power generation using an electret.
In Patent Literature 1, there is disclosed a power generation device to be used in a portable electric device, in which an electrode configured to integrally rotate with a rotary weight supported by a spiral spring is arranged so as to be opposed to an electret film.